Biology · Evolution · NEET
Both words appear here, but they answer different questions. Australian marsupials among THEMSELVES (one ancestor giving many marsupial forms) = adaptive radiation. When you compare a marsupial to a placental mammal that looks similar (e.g., Tasmanian wolf vs placental wolf), those two UNRELATED groups looking alike = convergent evolution. NCERT itself says: 'more than one adaptive radiation appeared to have occurred in an isolated geographical area (representing different habitats), one can call this convergent evolution.' So marsupials alone = adaptive radiation; marsupial-vs-placental resemblance = convergent evolution.
NCERT: 'A number of marsupials, each different from the other evolved from an ancestral stock, but all within the Australian island continent.' So the key idea NCERT wants is ONE ancestral marsupial stock radiating into MANY different marsupials. It is the same idea as Darwin's finches, where from an original seed-eating finch many beak forms arose.
Because Australia was an isolated island continent with many EMPTY (vacant) habitats and no placental competitors. That is exactly what NEET tests: an invading population radiates only when there are 'many types of vacant habitats' to move into. If habitats are already full of species, or there is a single vacant habitat, or very low food, radiation cannot happen.
In spirit yes, because one ancestor diverges into many. But NEET uses fixed labels: NCERT reserves 'divergent evolution' for homologous organs (same structure, different function, common ancestor, like forelimbs of man and whale). For the marsupial spreading story, always write 'adaptive radiation'. Do not answer 'divergent evolution' when the question shows Australian marsupials radiating.
NEET 2023 tested the exact set: Numbat, Spotted cuscus, Flying phalanger are genuine Australian marsupials. Also remember Tasmanian wolf (Thylacine, extinct), marsupial mole, Tasmanian tiger cat, and the kangaroo/koala group. Beware trap names like Bobcat, Mole, Flying squirrel, Lemur, Wolf, Anteater, Lemur which are PLACENTAL mammals, not marsupials.
Select the correct group/set of Australian Marsupials exhibiting adaptive radiation.
A population of a species invades a new area. Which of the following condition will lead to Adaptive Radiation?
Try the real previous-year questions from this chapter — each with the answer and a full solution.
It is the evolution of many different species from one ancestor in a given geographical area, starting from a point and spreading out ('radiating') to fill many different habitats.
Because they show the same pattern on a bigger scale: one ancestral marsupial stock diverged into many marsupials, each fitting a different habitat, all within one isolated island continent.
Yes. The kangaroo, koala, marsupial mole, numbat, Tasmanian wolf and others are all marsupial forms produced by this radiation from a common ancestral stock.
No. This is an NCERT exercise question. Humans did not diverge into many species filling many habitats from one point, so human evolution is not adaptive radiation.
Adaptive radiation is marsupials diversifying among themselves. Convergent evolution is a marsupial and an unrelated placental mammal (like Tasmanian wolf and placental wolf) ending up looking similar.
